body {        /*背景*/
    background-image: url('../images/4.jpg');
    background-size:cover;
}

#login {   /*黑色底*/
    width: 20%;
    height: 400px;
    background-color: #00000060;
    margin: auto;
    margin-top: 10%;
    text-align: center;
    border-radius: 10px;
    padding: 50px 50px;
}

h2 {   /*"卖家登录"*/
    color: white;
    margin-top: 5%;
}

#input {  /*请输入用户名*/
    margin-top: 5%;
}

span {   /*文字*/
    color: #fff;
}

input {  /*下划线*/
    border: 0;
    width: 60%;
    font-size: 15px;
    color: #fff;
    background: transparent;
    border-bottom: 2px solid #fff;
    padding: 5px 10px;
    outline: none;
    margin-top: 10px;
}

button {  /*确认按钮*/
    margin-top: 50px;
    width: 60%;
    height: 30px;
    border-radius: 10px;
    border: 0;
    color: #fff;
    text-align: center;
    line-height: 30px;
    font-size: 15px;
    background-image: linear-gradient(to right,rgb(0,135,181),rgb(0,190,255));
}

#sign_up {
    margin-top: 45%;
    margin-left: 60%;
}

#wrong {
    color: red;
}
